On 2008-09-23, Arfa Daily wrote:
"GregS" wrote in message
...
In article , Andre Majorel
wrote:
I'm trying to get a rough estimate of the rating of a
transformer.

It comes from an AKAI AT-M670L tuner. Transformer part number is
ST41007 TW; L350Y197H01; T 982 TK. No luck searching the web for
these.

Primary: 220 V / 50 Hz.
Secondary #1: 2 x 16.8 V loaded (2 x 5.75 ohm)
Secondary #2: 1 x 3.07 V loaded (2 x 1.5 ohm) (I guess for the VFD).
Fuses on secondary #2: 2 x 315 mA T
Weight: 252 g.
Windings size: about 25 x 25 x 15 mm.
Core size: about 42 x 33 x 22 mm.


I can't find where its in the S.E.R.

You find the voltage drop as you load the outputs
individually. The total load of all outputs will cut down on
the added individual outputs. Measure the output from no load
to drop voltage 10-20%, then measure or compute current.

Given that the transformer is likely to be over 85% efficient,
the input power consumption rating printed on the back of the
unit will give you a good idea of the VA rating of it

Well, there is none !

I expected you'd all take from the fuse rating. Interesting that
you didn't... (I made a mistake, BTW : the fuses are on the 16.8 V
windings.)

The measure-current-at-10-to-20%-lower-voltage-than-unloaded
method seems a little vague to me, not knowing what the V vs. I
curve looks like (I know very little about transformers).

Think I might as well increase the load until the transformer
becomes "too hot"...

--
André Majorel URL:http://www.teaser.fr/~amajorel/
"Je regrette le Concorde. Au moins il vous amenait directement à
l'hôtel." -- Cyrano